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ACTA AERONAUTICAET ASTRONAUTICA SINICA ›› 2015, Vol. 36 ›› Issue (5): 1713-1721.doi: 10.7527/S1000-6893.2014.0206

• Material Engineering and Mechanical Manufacturing • Previous Articles     Next Articles

Microstructure and property of surface layer produce during rare earths solid-state boriding of TC21 titanium alloy

CAI Wenjun1, LU Wenzhuang1,2, WANG Han1, ZHU Yansong1, ZUO Dunwen1   

  1. 1. College of Mechanical and Electrical Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China;
    2. Jiangsu Key Laboratory of Precision and Micro-Manufacturing Technology, Nanjing 210016, China
  • Received:2014-05-23 Revised:2014-08-25 Online:2015-05-15 Published:2014-09-11
  • Supported by:

    National Natural Science Foundation of China (51275230); Sustentation Fund Plan for Post Doctor of Jiangsu (1301028B); Foundation of Graduate Innovation Center in NUAA (kfjj20130216)

Abstract:

The rare earths (RE)-boronizing experiments are carried out for surface strengthening of TC21 titanium alloy. Microstructure, hardness, worn surfaces and specific wear rate of boride layers are studied. Results show that the boride layer with 7wt% content of CeO2 in the agent is continuous and compact and it has better wear resistance. Boronizing temperature has a significant effect on the thickness of TiB2 layer and the thickness of boride layer tends to significantly increase with it. As boronizing time goes on, the TiB2 layer in surface becomes deeper and more continuous, whereas the thickness of boride layer increases slowly after a certain time. The microhardness of top layer is significantly increased by raising boronizing temperature, but it rises gently with time passing. At 1 000 ℃, the microhardness of top layer is about 3 200 HV0.01 and the depth of high microhardness area is over 20 μm. The boride layer has a good wear resistance and specific wear rate of boride layers is 50-60 times lower than that of untreated specimen.

Key words: solid-state boriding, TC21 titanium alloy, RE, microstructure, friction and wear, microhardness

CLC Number: